# Is NOON written as 12AM or 12PM? **URL:** \ **Category:** Factual Questions\ **Created:** [October 4, 2000, 2:21am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566 "2000-10-04T02:21:38Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [October 4, 2000, 2:17pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/21 "2000-10-04T14:17:39Z")
> [@](#): > > \*Originally posted by friedo \* > \*\* > > > [@](#): > > > > \*Originally posted by AWB \* > > \*\*One millisecond after midnight is 12:00:00.000001 AM. So if the 12 o’clocks need to be AM or PM, midnight would be AM. \*\* > > That’s a few too many zeroes for a milisecond, but the premise is correct.\*\* **BUZZ!!** Minus two points for me. I was thinking “milli” was “millionth”, not “thousandth”. Damn the English language! :D:D ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [October 4, 2000, 2:24pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/22 "2000-10-04T14:24:14Z")
That 12 noon is “noon” and 12 midnight is “midnight” has never been in dispute. The question has been, when forced by circumstance to designate one as AM and one as PM, which is which? Or, when you see it written that way, which is it referring to? Obviously, your communication will suffer less ambiguity for some people (most know the difference) if you use the words “noon” and “midnight.” Nonetheless, for the purposes of answering the OP, “noon” unequivocally equals “12PM” and midnight unequivocally equals “12AM.” To use the opposite designations will cause the greatest confusion of all the offered alternatives, as it would simply be _wrong_: noon could not by any stretch of the imagination happen _before itself_, so it could by any stretch of the imagination be AM. On the other hand, though 12:00.0000000000[…] is neither AM nor PM, it also does not exist: time continues to move forward, for most of us, and by the time you say “noon” it’s afternoon–or PM. ---
**Author:** ![Joe\_Malik](https://avatars.discourse-cdn.com/v4/letter/j/48db29/32.png) [@Joe\_Malik](https://boards.straightdope.com/u/Joe_Malik)\ **Post date:** [October 4, 2000, 2:47pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/23 "2000-10-04T14:47:27Z")
lissener: add your argument to the fact that most every computer program in the world likes it that way and you have a pretty persuasive case. ---
**Author:** ![Drew\_Blade](https://avatars.discourse-cdn.com/v4/letter/d/958977/32.png) [@Drew\_Blade](https://boards.straightdope.com/u/Drew_Blade)\ **Post date:** [October 4, 2000, 2:49pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/24 "2000-10-04T14:49:04Z")
I like the noon and midnight designations, but my vcr requires me to choose 1 for am or 2 for pm. I have never put it to the test to see what it means by 12:00 am or 12:00 pm. Instead I always use 11:59 (am or pm) or 12:01 (am or pm). If I ever find out how my vcr treats 12:00 am and 12:00 pm, that will be the final word on the subject in my household. I am a servant of the technology around me! ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [October 4, 2000, 3:13pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/25 "2000-10-04T15:13:50Z")
[ol][li]On the threshhold of New Year’s Eve/New Year’s Day, people don’t wait a second (or millisecond or microsecond) after the clock changes to the hour of 12 to scream, “Happy New Year!” They do it exactly at 12.[/li][li]Therefore, 12:00 midnight is considered part of the next day.[/li][li]Being that it’s part of the next day, it is by observation before noon, _ante meridiem_, AM.[/li][/ol] And saying that AM is only for the 12 hours before noon, what about the day that most Americans switch back from Daylight Savings Time to Standard Time? There are 13 hours of AM those days. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 4, 2000, 4:37pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/26 "2000-10-04T16:37:30Z")
At noontime, a clock will read 12:00 for a period of sixty seconds. For the first instant of that interval, the AM/PM distinction is arbitrary, but at every instant thereafter, it is clearly after noon. Hence, for the infinitely overwhelming proportion of the time when a clock reads 12:00 noon, it’s PM, so 12:00 PM means 12 noon. Sorry, **nonoMAN** , but dictionaries can make mistakes, too. ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [October 4, 2000, 7:10pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/27 "2000-10-04T19:10:41Z")
On a related note (and to maybe help illustrate), is zero a positive or negative number? 🙂 ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [October 4, 2000, 11:41pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/28 "2000-10-04T23:41:56Z")
I just went into my bedroom and played with my alarm clock. Pretty exciting stuff, I’m here to tell ya! 🙂 Anyway, when the thing hits 12 midnight the PM indicator light goes off. And when it hits 12 noon, the light goes back on. Try it for yourself. That’s good enough for me. 😃 Sometimes you guys just gotta say “OK, you’re right”. Peace, mangeorge BTW; If the 24hr clock was correct, noon would be 0000 and midnight would be 1200. Ha. ---
**Author:** ![MrWhy](https://avatars.discourse-cdn.com/v4/letter/m/9f8e36/32.png) [@MrWhy](https://boards.straightdope.com/u/MrWhy)\ **Post date:** [October 5, 2000, 12:10am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/29 "2000-10-05T00:10:22Z")
> [@](#): > > \*Originally posted by Homer \* > \*\*What? That doesn’t make sense. > > 1 am is right after midnight. Zip down to 11 am, which is right before noon. Since 12 comes directly after 11, it is still am. We’ve started over, and now we’re at 1 pm. Zip up to 11, it’s still pm. 12 is STILL after 11, therefore, midnight is 12pm. > > \*\* This explanation has always made sense to me. The 12 in 12 noon is part of the run of numbers from 1am to 11am. So why would it not be am as well? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 5, 2000, 5:54am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/30 "2000-10-05T05:54:58Z")
> [@](#): > > 1 am is right after midnight. Zip down to 11 am, which is right before noon. Since 12 comes directly after 11, it is still am. We’ve started over, and now we’re at 1 pm. Zip up to 11, it’s still pm. 12 is STILL after 11, therefore, midnight is 12pm. And 1300 hours comes right after 12:00, and 1400 hours comes right after 1300. Does that mean they are AM as well? No. As has been pointed out many times, for all intents and purposes 1200 hours is 12:00 PM. ---
**Author:** ![Kupek](https://avatars.discourse-cdn.com/v4/letter/k/90db22/32.png) [@Kupek](https://boards.straightdope.com/u/Kupek)\ **Post date:** [October 5, 2000, 5:57am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/31 "2000-10-05T05:57:02Z")
If noon and midnight not having AM and PM identifiers bothers you, just ask yourself this: Is zero positive or negative? ---
**Author:** ![Kupek](https://avatars.discourse-cdn.com/v4/letter/k/90db22/32.png) [@Kupek](https://boards.straightdope.com/u/Kupek)\ **Post date:** [October 5, 2000, 6:00am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/32 "2000-10-05T06:00:32Z")
\*1.On the threshhold of New Year’s Eve/New Year’s Day, people don’t wait a second (or millisecond or microsecond) after the clock changes to the hour of 12 to scream, “Happy New Year!” They do it exactly at 12. 2.Therefore, 12:00 midnight is considered part of the next day. 3.Being that it’s part of the next day, it is by observation before noon, ante meridiem, AM. \* Exactly at 12? Not hardly. The do it at the moment they realize the clock has changed, and at that moment, the instant in time known as midnight has passed, and we’re well into AM, the next day. Remember that midnight is an instance in time, not a span of time. (Yeah, I’ve already posted, and yeah, my first ended up being redundant. Moral: Read the whole thread first.) ---
**Author:** ![ricepad](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@ricepad](https://boards.straightdope.com/u/ricepad)\ **Post date:** [October 5, 2000, 6:02am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/33 "2000-10-05T06:02:15Z")
> [@](#): > > \*Originally posted by Kupek \* > \*\*If noon and midnight not having AM and PM identifiers bothers you, just ask yourself this: Is zero positive or negative? \*\* You betcha! ---
**Author:** ![lawoot](https://avatars.discourse-cdn.com/v4/letter/l/35a633/32.png) [@lawoot](https://boards.straightdope.com/u/lawoot)\ **Post date:** [October 5, 2000, 6:35am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/34 "2000-10-05T06:35:41Z")
> [@](#): > > \*Originally posted by Derleth \* > \*\* > > > [@](#): > > > > BYW; Military time sucks. > > -mangeorge > > I use 24 hour time. Noon is 1200 and midnight is 0000. This problem never once comes up. So ha! 😃 \*\* we use a 24 hour clock where I work… and noon is 1200, but midnight is 2400. one minute after is 0001. What is the actual, ‘official’ military designation? ---
**Author:** ![Danielinthewolvesden](https://avatars.discourse-cdn.com/v4/letter/d/ce7236/32.png) [@Danielinthewolvesden](https://boards.straightdope.com/u/Danielinthewolvesden)\ **Post date:** [October 5, 2000, 8:15am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/35 "2000-10-05T08:15:32Z")
12noon+ 12NN, not 12PM 12midnite= 12MN, not12AM ---
**Author:** ![nonoMAN](https://avatars.discourse-cdn.com/v4/letter/n/8dc957/32.png) [@nonoMAN](https://boards.straightdope.com/u/nonoMAN)\ **Post date:** [October 5, 2000, 8:23am UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/36 "2000-10-05T08:23:14Z")
All I’m hearing is a bunch of speculation. People have made marginally convincing arguments in both directions. So, I ask you, what source would convince you to change your position? I ask in the hopes of seeing a quoted source other than some alarm clock made in Taiwan for 4cents on the dollar. ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [October 5, 2000, 1:55pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/37 "2000-10-05T13:55:07Z")
> [@](#): > > \*Originally posted by cornflakes \* > \*\*On a related note (and to maybe help illustrate), is zero a positive or negative number? 🙂 \*\* To paraphrase the Guardian of Forever: “It is both, and neither.” Here’s a definition that basically says it can be both: _If **a** is a number, positive, negative, or zero, then **b** is the negative of **a** if **a** _ + **b** = 0.\* So, zero is it’s own negative. I guess. :rolleyes: ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 5, 2000, 2:29pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/38 "2000-10-05T14:29:44Z")
Okay, I’ve sent an e-mail to the U.S. Naval Observatory, who are the official timekeepers in this country. When and if they reply, I’ll post the answer here. But trust me for now. Midnight is AM and noon is PM. ---
**Author:** ![Kupek](https://avatars.discourse-cdn.com/v4/letter/k/90db22/32.png) [@Kupek](https://boards.straightdope.com/u/Kupek)\ **Post date:** [October 5, 2000, 9:34pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/39 "2000-10-05T21:34:03Z")
**AWB** : \*If a is a number, positive, negative, or zero, then b is the negative of a if a + b = 0. So, zero is it’s own negative. I guess.\* No, it’s a false statement. There is no negative of zero. To make it a true statement, you have to _exclude_ zero. ---
**Author:** ![BornDodgy](https://avatars.discourse-cdn.com/v4/letter/b/e19b73/32.png) [@BornDodgy](https://boards.straightdope.com/u/BornDodgy)\ **Post date:** [October 5, 2000, 9:42pm UTC](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566/40 "2000-10-05T21:42:04Z")
you are hurting my head. [Previous page](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566.md?page=1) [Next page](https://boards.straightdope.com/t/is-noon-written-as-12am-or-12pm/35566.md?page=3)